Fuel, communications, and power connection systems

ABSTRACT

Embodiments of systems and methods for supplying fuel, enabling communications, and conveying electric power associated with operation of a hydraulic fracturing unit of a plurality of hydraulic fracturing units are disclosed and may include a fuel line connection assembly configured to be connected to the first hydraulic fracturing unit and to supply fuel from a fuel source to a gas turbine engine connected to the hydraulic fracturing unit. A system also may include a communications cable assembly configured to be connected to the hydraulic fracturing unit and to enable data communications between the hydraulic fracturing unit and a data center or another hydraulic fracturing unit. A system further may include a power cable assembly configured to be connected to the hydraulic fracturing unit and to convey electric power between the hydraulic fracturing unit and a remote electrical power source or the plurality of hydraulic fracturing units.

PRIORITY CLAIM

This is a continuation of U.S. Non-Provisional application Ser. No.15/929,708, filed May 18, 2020, titled “FUEL, COMMUNICATIONS, AND POWERCONNECTION SYSTEMS AND RELATED METHODS,” which claims priority to andthe benefit of U.S. Provisional application Ser. No. 62/900,100, filedSep. 13, 2019, titled “ON BOARDING HOSES AND ELECTRICAL CONNECTIONS”,U.S. Provisional application Ser. No. 62/900,112, filed Sep. 13, 2019,titled “FUEL LINE CONNECTION SYSTEM AND METHODS FOR SAME”, and U.S.Provisional application Ser. No. 62/704,401, filed May 8, 2020, titled“FUEL, COMMUNICATIONS, AND POWER CONNECTION SYSTEMS AND RELATEDMETHODS”, the entire disclosures of all of which are incorporated hereinby reference.

TECHNICAL FIELD

The present disclosure relates to systems and methods for supplyingfuel, enabling communications, and/or conveying electric power tomachines, and more particularly, to systems and methods for supplyingfuel, enabling communications, and/or conveying electric power to aplurality of hydraulic fracturing units.

BACKGROUND

Fracturing is an oilfield operation that stimulates production ofhydrocarbons, such that the hydrocarbons may more easily or readily flowfrom a subsurface formation to a well. For example, a fracturing systemmay be configured to fracture a formation by pumping a fracking fluidinto a well at high pressure and high flow rates. Some fracking fluidsmay take the form of a slurry including water, proppants, and/or otheradditives, such as thickening agents and/or gels. The slurry may beforced via one or more pumps into the formation at rates faster than canbe accepted by the existing pores, fractures, faults, or other spaceswithin the formation. As a result, pressure builds rapidly to the pointwhere the formation fails and begins to fracture. By continuing to pumpthe fracking fluid into the formation, existing fractures in theformation are caused to expand and extend in directions farther awayfrom a well bore, thereby creating flow paths to the well bore. Theproppants may serve to prevent the expanded fractures from closing whenpumping of the fracking fluid is ceased or may reduce the extent towhich the expanded fractures contract when pumping of the fracking fluidis ceased. Once the formation is fractured, large quantities of theinjected fracking fluid are allowed to flow out of the well, and theproduction stream of hydrocarbons may be obtained from the formation.

A fracturing system includes a large number of separate componentsrequired for executing a fracturing operation, each of which must betransported to the fracturing site in an at least partially disassembledstate, assembled, and provided with a supply of fuel and electricity foroperation, as well as data communications links for controlling theoperation. Providing fuel delivery lines, communications links, andelectric power to and between the numerous components when setting-upthe fracturing operation requires a significant number of skilledpersonnel, numerous tools, and a substantial amount of time, allcontributing significantly to the cost of the fracturing operation.Following completion of the fracturing operation, the components must bebroken-down and transported from the fracturing site to anotherfracturing site. Thus, significant time and cost are involved withsetting-up and tearing-down the fracturing operation. In addition,depending on the requirements of a particular operation and the site onwhich it occurs, different a fracturing operations may require differentcomponents and arrangements, which may add complexity to setting-up andtearing-down the fracturing operation, further adding to the time andcosts associated with the fracturing operation.

Accordingly, it can be seen that a need exists for systems and methodsthat provide greater efficiency when setting-up and tearing-downcomponents associated with a fracturing operation. The presentdisclosure may address one or more of the above-referenced drawbacks, aswell as other possible drawbacks.

SUMMARY

The present disclosure is generally directed to systems and methods forsupplying fuel, enabling communications, and/or conveying electric powerto machines, and more particularly, to a plurality of hydraulicfracturing units associated with a hydraulic fracturing system. Forexample, in some embodiments, a fuel line connection assembly forproviding flow communication between a fuel source and a first gasturbine engine of a plurality of gas turbine engines may include amanifold line defining an inlet end, an outlet end, and a flow path forfuel extending between the inlet end and the outlet end. The fuel lineconnection assembly may further include an inlet coupling proximate theinlet end and configured to be connected to a fuel line providing flowcommunication with the fuel source, and an outlet coupling proximate theoutlet end and configured to be connected to one of an inlet end ofanother manifold line or a blocking device configured to prevent flowfrom the outlet end of the manifold line. The fuel line connectionassembly may further include a distribution line connected to themanifold line and configured to provide flow communication between themanifold line and the first gas turbine engine, and a valve in one ofthe manifold line or the distribution line and configured to changebetween an open condition through which fluid flows and a closedcondition preventing fluid flow. The valve may be configured to one offacilitate flow communication or prevent flow communication between thefuel source and the first gas turbine engine. The fuel line connectionassembly may be configured to one of: (1) provide flow communicationbetween a second gas turbine engine of the plurality of gas turbineengines upstream of the first gas turbine engine and a third gas turbineengine of the plurality of gas turbine engines downstream of the firstgas turbine engine; or (2) provide flow communication solely between thefuel source and the first gas turbine engine.

According some embodiments, a fuel delivery system configured to supplyfuel to a plurality of gas turbine engines connected to a plurality ofpumps of a hydraulic fracturing system may include a plurality of fuelline connection assemblies. The fuel line connection assemblies mayinclude a manifold line defining an inlet end, an outlet end, and a flowpath for fuel extending between the inlet end and the outlet end. Thefuel line connection assembly may also include an inlet couplingproximate the inlet end and configured to be connected to a fuel lineproviding flow communication with the fuel source, and an outletcoupling proximate the outlet end and configured to be connected to oneof an inlet end of another manifold line or a blocking device configuredto prevent flow from the outlet end of the manifold line. The fuel lineconnection assembly may also include a distribution line connected tothe manifold line and configured to provide flow communication betweenthe manifold line and the first gas turbine engine, and a valve in oneof the manifold line or the distribution line and configured to changebetween an open condition through which fluid flows and a closedcondition preventing fluid flow. The valve may be further configured toone of facilitate flow communication or prevent flow communicationbetween the fuel source and the first gas turbine engine. A first fuelline connection assembly of the plurality of fuel line connectionassemblies may be in flow communication with a first outlet coupling ofthe fuel source via an inlet coupling of the first fuel line connectionassembly. A second fuel line connection assembly of the plurality offuel line connection assemblies may be in flow communication with one ofan outlet coupling of the first fuel line connection assembly or asecond outlet coupling of the fuel source via an inlet coupling of thesecond fuel line connection assembly.

According to some embodiments, a method for pressure testing at least aportion of a fuel delivery system for supplying fuel from a fuel sourceto a plurality of gas turbine engines may include causing a first valveto be in an open condition. The first valve may be configured to one offacilitate flow communication or prevent flow communication between thefuel source and a first gas turbine engine of the plurality of gasturbine engines. The method may further include causing a second valveto be in a closed condition. The second valve may be configured to oneof facilitate flow communication or prevent flow communication between afilter configured to filter one or more of particulates or liquids fromfuel and the first gas turbine engine. The method may further includecausing a third valve to be in an open condition. The third valve may beconfigured to one of facilitate flow communication or prevent flowcommunication between a pressure source and the filter. The method mayfurther include increasing pressure via the pressure source in the atleast a portion of the fuel delivery system, and monitoring a signalindicative of pressure in the at least a portion of the fuel deliverysystem. The method may also include, based at least in part on thesignal, determining whether the at least a portion of the fuel deliverysystem has a leak.

According to some embodiments, a system for supplying fuel, enablingcommunications, and conveying electric power associated with operationof a hydraulic fracturing unit associated with a plurality of hydraulicfracturing units may include a fuel line connection assembly configuredto be connected to the hydraulic fracturing unit and to supply fuel froma fuel source to a first gas turbine engine connected to the hydraulicfracturing unit. The fuel line connection assembly may include amanifold line defining an inlet end, an outlet end, and a flow path forfuel extending between the inlet end and the outlet end. The fuelconnection assembly may also include a distribution line connected tothe manifold line and configured to provide flow communication betweenthe manifold line and the first gas turbine engine. The fuel lineconnection assembly may be configured to one of: (1) provide flowcommunication between one of the fuel source or a second gas turbineengine of the plurality of the hydraulic fracturing units upstream ofthe first gas turbine engine and a third gas turbine engine of theplurality of hydraulic fracturing units downstream of the first gasturbine engine; or (2) provide flow communication solely between thefuel source and the first gas turbine engine. The system may alsoinclude a communications cable assembly configured to be connected tothe hydraulic fracturing unit and to enable data communications betweenthe hydraulic fracturing unit and one of a data center remote from thehydraulic fracturing unit or a second hydraulic fracturing unit of theplurality of hydraulic fracturing units. The communications cableassembly may include a length of communications cable and acommunications cable storage apparatus configured to be connected to thehydraulic fracturing unit, to store the length of communications cablewhen not in use, and to facilitate deployment of at least a portion ofthe length of communications cable for connection to the one of the datacenter or the second hydraulic fracturing unit. The system may alsoinclude a power cable assembly configured to be connected to thehydraulic fracturing unit and to convey electric power between thehydraulic fracturing unit and one or more of a remote electrical powersource or one or more of the plurality of hydraulic fracturing units.The power cable assembly may include a length of power cable and a powercable storage apparatus configured to be connected to the hydraulicfracturing unit, to store the length of power cable when not in use, andto facilitate deployment of at least a portion of the length of powercable for use.

According to some embodiments, a hydraulic fracturing unit may include achassis, a pump connected to the chassis and configured to pump afracturing fluid, and a first gas turbine engine connected to thechassis and configured to convert fuel into a power output for operatingthe pump. The hydraulic fracturing unit may also include a system forsupplying fuel, enabling communications, and conveying electric powerassociated with operation of the hydraulic fracturing unit. The systemmay include a fuel line connection assembly connected to the hydraulicfracturing unit and configured to supply fuel from a fuel source to thefirst gas turbine engine connected to the chassis. The fuel lineconnection assembly may include a manifold line defining an inlet end,an outlet end, and a flow path for fuel extending between the inlet endand the outlet end. The fuel line connection assembly may also include adistribution line connected to the manifold line and configured toprovide flow communication between the manifold line and the first gasturbine engine. The fuel line connection assembly may be configured toone of: (1) provide flow communication between one of the fuel source ora second gas turbine engine of a second hydraulic fracturing unitupstream of the first gas turbine engine and a third gas turbine engineof a hydraulic fracturing unit downstream of the first gas turbineengine; or (2) provide flow communication solely between the fuel sourceand the first gas turbine engine. The system may also include acommunications cable assembly connected to the hydraulic fracturing unitand configured to enable data communications between the hydraulicfracturing unit and one of a data center remote from the hydraulicfracturing unit or an additional hydraulic fracturing unit. Thecommunications cable assembly may include a length of communicationscable and a communications cable storage apparatus connected to thehydraulic fracturing unit and configured to store the length ofcommunications cable when not in use and to facilitate deployment of atleast a portion of the length of communications cable for connection tothe one of the data center or the another hydraulic fracturing unit. Thesystem may also include a power cable assembly connected to thehydraulic fracturing unit and configured to convey electric powerbetween the hydraulic fracturing unit and one or more of a remoteelectrical power source or one or more additional hydraulic fracturingunits. The power cable assembly may include a length of power cable anda power cable storage apparatus connected to the hydraulic fracturingunit and configured to store the length of power cable when not in useand facilitate deployment of at least a portion of the length of powercable for use.

According to some embodiments, a hydraulic fracturing system may includea plurality of hydraulic fracturing units. The hydraulic fracturingsystem may include a main fuel line configured to supply fuel from afuel source to a plurality of hydraulic fracturing units. The hydraulicfracturing system may also include a first hydraulic fracturing unitincluding a chassis, a pump connected to the chassis and configured topump fracturing fluid, and a first gas turbine engine connected to thechassis and configured to convert fuel into a power output for operatingthe pump. The hydraulic fracturing system may also include a system forsupplying fuel, enabling communications, and conveying electric powerassociated with operation of the first hydraulic fracturing unit. Thesystem may include a fuel line connection assembly connected to thefirst hydraulic fracturing unit and configured to supply fuel from thefuel source to the first gas turbine engine. The fuel line connectionassembly may include a manifold line defining an inlet end, an outletend, and a flow path for fuel extending between the inlet end and theoutlet end. The manifold line may be configured to provide at least aportion of a flow path for supplying fuel to the first gas turbineengine. The fuel line connection assembly may be configured to one of:(1) provide flow communication between one of the main fuel line or asecond gas turbine engine of a second hydraulic fracturing unit upstreamof the first gas turbine engine and a third gas turbine engine of athird hydraulic fracturing unit downstream of the first gas turbineengine; or (2) provide flow communication solely between the main fuelline and the first gas turbine engine. The system may also include acommunications cable assembly including a length of communications cableconnected to the first hydraulic fracturing unit and configured toenable data communications between the first hydraulic fracturing unitand one of a data center remote from the first hydraulic fracturing unitor one or more additional hydraulic fracturing units of the plurality ofhydraulic fracturing units. The system may also include a power cableassembly including a length of power cable connected to the firsthydraulic fracturing unit and configured to convey electric powerbetween the first hydraulic fracturing unit and one or more of a remoteelectrical power source or one or more additional hydraulic fracturingunits of the plurality of hydraulic fracturing units. The hydraulicfracturing system may also include a data center configured to one ormore of transmit communications signals or receive communicationssignals. The communications signals may include data indicative ofoperation of one or more of the plurality of hydraulic fracturing units.

Still other aspects, embodiments, and advantages of these exemplaryembodiments and embodiments, are discussed in detail below. Moreover, itis to be understood that both the foregoing information and thefollowing detailed description provide merely illustrative examples ofvarious aspects and embodiments, and are intended to provide an overviewor framework for understanding the nature and character of the claimedaspects and embodiments. Accordingly, these and other objects, alongwith advantages and features of the present invention herein disclosed,will become apparent through reference to the following description andthe accompanying drawings. Furthermore, it is to be understood that thefeatures of the various embodiments described herein are not mutuallyexclusive and can exist in various combinations and permutations.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the embodiments of the present disclosure, areincorporated in and constitute a part of this specification, illustrateembodiments of the present disclosure, and together with the detaileddescription, serve to explain principles of the embodiments discussedherein. No attempt is made to show structural details of this disclosurein more detail than can be necessary for a fundamental understanding ofthe embodiments discussed herein and the various ways in which they canbe practiced. According to common practice, the various features of thedrawings discussed below are not necessarily drawn to scale. Dimensionsof various features and elements in the drawings can be expanded orreduced to more clearly illustrate embodiments of the disclosure.

FIG. 1 schematically illustrates an example fuel delivery system forsupplying fuel to a plurality of hydraulic fracturing units, including adetailed schematic view of an example fuel line connection assemblyaccording to embodiments of the disclosure.

FIG. 2A is a schematic view of an example fuel line connection assemblyin an example first condition for operation of a gas turbine engineaccording to embodiments of the disclosure.

FIG. 2B is a schematic view of the example fuel line connection assemblyshown in FIG.

2A in an example second condition during an example pressure testingprocedure.

FIG. 3 is a perspective view of an example fuel line connection assemblyaccording to embodiments of the disclosure.

FIG. 4 is a schematic diagram showing an example fuel delivery systemfor supplying fuel to a plurality of hydraulic fracturing unitsaccording to embodiments of the disclosure.

FIG. 5 is a schematic diagram showing another example fuel deliverysystem for supplying fuel to a plurality of hydraulic fracturing unitsaccording to embodiments of the disclosure.

FIG. 6 is a schematic diagram showing a further example fuel deliverysystem for supplying fuel to a plurality of hydraulic fracturing unitsaccording to embodiments of the disclosure.

FIG. 7 is a schematic diagram showing another example fuel deliverysystem for supplying fuel to a plurality of hydraulic fracturing unitsaccording to embodiments of the disclosure.

FIG. 8 is a block diagram of an example method for pressure testing atleast a portion of an example fuel delivery system for supplying fuelfrom a fuel source to a plurality of gas turbine engines according toembodiments of the disclosure.

FIG. 9 is a schematic diagram showing an example system for supplyingfuel, enabling communications, and conveying electric power associatedwith operation of a plurality of hydraulic fracturing units according toembodiments of the disclosure.

FIG. 10 is a schematic diagram showing another example system forsupplying fuel, enabling communications, and conveying electric powerassociated with operation of a plurality of hydraulic fracturing unitsaccording to embodiments of the disclosure.

FIG. 11 is a schematic diagram showing a further example system forsupplying fuel, enabling communications, and conveying electric powerassociated with operation of a plurality of hydraulic fracturing unitsaccording to embodiments of the disclosure.

FIG. 12 is a schematic diagram showing another example system forsupplying fuel, enabling communications, and conveying electric powerassociated with operation of a plurality of hydraulic fracturing unitsaccording to embodiments of the disclosure.

FIG. 13 is a schematic diagram showing a further example system forsupplying fuel, enabling communications, and conveying electric powerassociated with operation of a plurality of hydraulic fracturing unitsaccording to embodiments of the disclosure.

FIG. 14 is a schematic diagram showing another example system forsupplying fuel, enabling communications, and conveying electric powerassociated with operation of a plurality of hydraulic fracturing unitsaccording to embodiments of the disclosure.

FIG. 15 is a schematic diagram showing a further example system forsupplying fuel, enabling communications, and conveying electric powerassociated with operation of a plurality of hydraulic fracturing unitsaccording to embodiments of the disclosure.

FIG. 16 is a schematic diagram showing another example system forsupplying fuel, enabling communications, and conveying electric powerassociated with operation of a plurality of hydraulic fracturing unitsaccording to embodiments of the disclosure.

FIG. 17A is a perspective view of an example quick connect coupling forcoupling two fuel lines to one another shown in an uncoupled conditionaccording to embodiments of the disclosure.

FIG. 17B is a perspective view of the example quick connect couplingshown in FIG. 17A shown in a coupled condition according to embodimentsof the disclosure.

FIG. 17C is a perspective view of another example quick connect couplingfor coupling two fuel lines to one another shown in an uncoupledcondition according to embodiments of the disclosure.

FIG. 18 is a perspective view of an example communications coupling fora communications cable according to embodiments of the disclosure.

FIG. 19 is a perspective view of an example power coupling for couplinga power cable shown in an uncoupled condition according to embodimentsof the disclosure.

DETAILED DESCRIPTION

Referring now to the drawings in which like numerals indicate like partsthroughout the several views, the following description is provided asan enabling teaching of exemplary embodiments, and those skilled in therelevant art will recognize that many changes can be made to theembodiments described. It also will be apparent that some of the desiredbenefits of the embodiments described can be obtained by selecting someof the features of the embodiments without utilizing other features.Accordingly, those skilled in the art will recognize that manymodifications and adaptations to the embodiments described are possibleand can even be desirable in certain circumstances. Thus, the followingdescription is provided as illustrative of the principles of theembodiments and not in limitation thereof.

The phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. As used herein, theterm “plurality” refers to two or more items or components. The terms“comprising,” “including,” “carrying,” “having,” “containing,” and“involving,” whether in the written description or the claims and thelike, are open-ended terms, i.e., to mean “including but not limitedto,” unless otherwise stated. Thus, the use of such terms is meant toencompass the items listed thereafter, and equivalents thereof, as wellas additional items. The transitional phrases “consisting of” and“consisting essentially of,” are closed or semi-closed transitionalphrases, respectively, with respect to any claims. Use of ordinal termssuch as “first,” “second,” “third,” and the like in the claims to modifya claim element does not by itself connote any priority, precedence, ororder of one claim element over another or the temporal order in whichacts of a method are performed, but are used merely as labels todistinguish one claim element having a certain name from another elementhaving a same name (but for use of the ordinal term) to distinguishclaim elements.

FIG. 1 schematically illustrates an example fuel delivery system 10 forsupplying fuel to a plurality of hydraulic fracturing units 12,including a detailed schematic view of an example fuel line connectionassembly 14 according to embodiments of the disclosure. The fueldelivery system 10 may be part of a hydraulic fracturing system 16 thatincludes a plurality (or fleet) of hydraulic fracturing units 12configured to pump a fracking fluid into a well at high pressure andhigh flow rates, so that a subterranean formation fails and begins tofracture in order to promote hydrocarbon production from the well.

In some examples, one or more of the hydraulic fracturing units 12 mayinclude directly driven turbine (DDT) pumping units, in which pumps 18are connected to one or more gas turbine engines (GTEs) 20 that supplypower to the respective pump 18 for supplying fracking fluid at highpressure and high flow rates to a formation. For example, a GTE 20 maybe connected to a respective pump 18 via a reduction transmissionconnected to a drive shaft, which, in turn, is connected to an inputshaft or input flange of a respective reciprocating pump 18. Other typesof GTE-to-pump arrangements are contemplated. In some examples, one ormore of the GTEs 20 may be a dual-fuel or bi-fuel GTE, for example,capable of being operated using of two or more different types of fuel,such as natural gas and diesel fuel, although other types of fuel arecontemplated. For example, a dual-fuel or bi-fuel GTE may be capable ofbeing operated using a first type of fuel, a second type of fuel, and/ora combination of the first type of fuel and the second type of fuel. Forexample, the fuel may include compressed natural gas (CNG), natural gas,field gas, pipeline gas, methane, propane, butane, and/or liquid fuels,such as, for example, diesel fuel (e.g., #2 Diesel), bio-diesel fuel,bio-fuel, alcohol, gasoline, gasohol, aviation fuel, etc. Gaseous fuelsmay be supplied by CNG bulk vessels, a gas compressor, a liquid naturalgas vaporizer, line gas, and/or well-gas produced natural gas. Othertypes and sources of fuel are contemplated. The one or more GTEs 20 maybe operated to provide horsepower to drive via a transmission one ormore of the pumps 18 to safely and successfully fracture a formationduring a well stimulation project.

Although not shown in FIG. 1, the hydraulic fracturing system 16 mayinclude a plurality of water tanks for supplying water for a frackingfluid, one or more chemical tanks for supplying gels or agents foradding to the fracking fluid, and a plurality of proppant tanks (e.g.,sand tanks) for supplying proppants for the fracking fluid. Thehydraulic fracturing system 16 may also include a hydration unit formixing water from the water tanks and gels and/or agents from thechemical tank to form a mixture, for example, gelled water. Thehydraulic fracturing system 16 may also include a blender, whichreceives the mixture from the hydration unit and proppants via conveyersfrom the proppant tanks. The blender may mix the mixture and theproppants into a slurry to serve as fracking fluid for the hydraulicfracturing system 16. Once combined, the slurry may be dischargedthrough low-pressure hoses, which convey the slurry into two or morelow-pressure lines in a frac manifold 24, as shown in FIG. 1.Low-pressure lines in the frac manifold 24 feed the slurry to theplurality of pumps 18 shown in FIG. 1 through low-pressure suctionhoses.

FIG. 1 shows an example fuel delivery system 10 associated with aplurality, or fleet, of example hydraulic fracturing units 12 accordingto embodiments of the disclosure, identified as 12 a, 12 b, 12 c, 12 d,12 e, 12 f, 12 g, and 12 h, although fewer or more hydraulic fracturingunits 12 are contemplated. In the example shown, each of the pluralityhydraulic fracturing units 12 includes a GTE 20, identified respectivelyas 20 a, 20 b, 20 c, 20 d, 20 e, 20 f, 20 g, and 20 h. Each of the GTEs20 supplies power for each of the hydraulic fracturing units 12 tooperate a pump 18, identified respectively as 18 a, 18 b, 18 c, 18 d, 18e, 18 f, 18 g, and 18 h.

The pumps 18 are driven by the GTEs 20 of the respective hydraulicfracturing units 12 and discharge the slurry (e.g., the fracking fluidincluding the water, agents, gels, and/or proppants) at high pressureand/or a high flow rates through individual high-pressure dischargelines 26 into two or more high-pressure flow lines 28, sometimesreferred to as “missiles,” on the frac manifold 24. The flow from theflow lines 28 is combined at the frac manifold 24, and one or more ofthe flow lines 28 provide flow communication with a manifold assembly,sometimes referred to as a “goat head.” The manifold assembly deliversthe slurry into a wellhead manifold, sometimes referred to as a “zippermanifold” or a “frac manifold.” The wellhead manifold may be configuredto selectively divert the slurry to, for example, one or more well headsvia operation of one or more valves. Once the fracturing process isceased or completed, flow returning from the fractured formationdischarges into a flowback manifold, and the returned flow may becollected in one or more flowback tanks.

In the example shown in FIG. 1, one or more of the components of thehydraulic fracturing system 16 may be configured to be portable, so thatthe hydraulic fracturing system 16 may be transported to a well site,assembled, operated for a relatively short period of time, at leastpartially disassembled, and transported to another location of anotherwell site for use. In the example shown in FIG. 1, each of the pumps 18and GTEs 20 of a respective hydraulic fracturing unit 12 may beconnected to (e.g., mounted on) a chassis 30, identified respectively as30 a, 30 b, 30 c, 30 d, 30 e, 30 f, 30 g, and 30 h. In some examples,the chassis 30 may include a trailer (e.g., a flat-bed trailer) and/or atruck body to which the components of a respective hydraulic fracturingunit 12 may be connected. For example, the components may be carried bytrailers and/or incorporated into trucks, so that they may be easilytransported between well sites.

As shown in FIG. 1, the example fuel delivery system 10 may include aplurality of fuel line connection assemblies 14, for example, forfacilitating the supply of fuel from the fuel source 22 to each of theGTEs 20 of the hydraulic fracturing system 16. In some examples, forexample, as shown in FIGS. 1, 2A, 2B, and 3, one or more of the fuelline connection assemblies 14 may include a manifold line 32 defining aninlet end 34, an outlet end 36, and a flow path 38 for fuel extendingbetween the inlet end 36 and the outlet end 38. In addition, the fuelline connection assemblies 14 may include an inlet coupling 40 proximatethe inlet end 34 and configured to be connected to a fuel line 42providing flow communication with the fuel source 22, and an outletcoupling 44 proximate the outlet end 36 and configured to be connectedto an inlet end of another manifold line or a blocking device configuredto prevent flow from the outlet end 36 of the manifold line 32, forexample, as explained in more detail herein.

For example, as shown in FIG. 1, the fuel delivery system 10 may includea fuel line connection assembly 14 associated with each of the hydraulicfracturing units 12 a through 12 h. In the example configuration shownin FIG. 1, a first hydraulic fracturing unit 12 a may be in flowcommunication with the fuel source 22 via the fuel line 42 (e.g., viafuel line 42 a). The inlet coupling 40 of the first hydraulic fracturingunit 12 a may be coupled to the fuel line 42 a. The outlet coupling 44for the first hydraulic fracturing unit 12 a may be coupled to an inletcoupling of a manifold line of a second hydraulic fracturing unit 12 b.Similarly, the outlet coupling of the second hydraulic fracturing unit12 b may be coupled to the inlet coupling of a manifold line of a thirdhydraulic fracturing unit 12 c. The outlet coupling of the manifold lineof the third hydraulic fracturing unit 12 c may be coupled to an inletcoupling of a manifold line of a fourth hydraulic fracturing unit 12 d.

In the example shown, the first through fourth hydraulic fracturingunits 12 a through 12 d may make up a first bank 46 of the hydraulicfracturing units 12, and fifth through eighth hydraulic fracturing units12 e through 12 h may make up a second bank 48 of the hydraulicfracturing units 12. In some examples, for example, as shown in FIG. 1,a fifth hydraulic fracturing unit 12 e may be in flow communication withthe fuel source 22 via the fuel line 42 (e.g., via fuel line 42 b). Theinlet coupling of the fifth hydraulic fracturing unit 12 e may becoupled to the fuel line 42. The outlet coupling for the fifth hydraulicfracturing unit 12 e may be coupled to an inlet coupling of a manifoldline of a sixth hydraulic fracturing unit 12 f. Similarly, the outletcoupling of the sixth hydraulic fracturing unit 12 f may be coupled toan inlet coupling of a manifold line of a seventh hydraulic fracturingunit 12 g. The outlet coupling of the manifold line of the seventhhydraulic fracturing unit 12 g may be coupled to an inlet coupling of amanifold line of an eighth hydraulic fracturing unit 12 h. The examplefuel delivery system 10 shown in FIG. 1 may sometimes be referred to asa “daisy-chain” arrangement.

In this example manner, the fuel source 22 may supply fuel to the GTEs20 of the hydraulic fracturing units 12. In some examples, fuel thatreaches the end of the first bank 46 of the hydraulic fracturing units12 remote from the fuel source 22 (e.g., the fourth hydraulic fracturingunit 12 d) and/or fuel that reaches the end of the second bank 48 of thehydraulic fracturing units 12 remote from the fuel source 22 (e.g., theeighth hydraulic fracturing unit 12 h) may be combined and/ortransferred between the first bank 46 and the second bank 48, forexample, via a transfer line 50 configured to provide flow communicationbetween the first bank 46 and the second bank 48. For example, unusedfuel supplied to either of the first bank 46 or the second bank 48 ofhydraulic fracturing units 12 may be passed to the other bank of the twobanks.

In some examples, the inlet coupling 40 and/or the outlet coupling 44may include a flange configured to be secured to another flange ofanother manifold line and/or a fuel line. For example, the manifold line32 may be a four-inch schedule 40 steel pipe, and the inlet coupling 40and/or the outlet coupling 44 may include a four-inch 300 class weldneck flange, although other manifold line types and sizes arecontemplated, as well as other coupling types and sizes. In someexamples, the inlet coupling 40 may include a quick connect couplingconfigured to connect the inlet end 34 of the manifold line 32 in afluid-tight manner with a quick connect coupling (e.g., a complimentarycoupling) of an outlet end of another manifold line. In some examples,the outlet coupling 44 may include quick connect coupling configured toconnect the outlet end 36 of the manifold line 32 in a fluid-tightmanner with a quick connect coupling of an inlet end of yet anothermanifold line and/or a quick connect coupling of a blocking deviceconfigured to prevent flow from the outlet end 36 of the manifold line32, for example, to effectively prevent flow through the manifold line32 to another hydraulic fracturing unit 12 of a common hydraulicfracturing system 16. In some examples, the quick connect coupling mayinclude a quarter-turn quick connect (e.g., a twister locking quickconnect) or a safety quick coupler (e.g., transfer-loading safety quickcoupling), for example, as disclosed herein with respect to FIGS. 17A,17B, and 17C.

In addition, as shown in FIGS. 1, 2A, 2B, and 3, the fuel lineconnection assemblies 14 may include a distribution line 52 connected tothe manifold line 32 and configured to provide flow communicationbetween the manifold line 32 and a GTE 20 of the respective hydraulicfracturing unit 12. In some examples, the fuel line connection assembly14 may also include a valve 54 in the manifold line 32 or thedistribution line 52 and configured to change between an open conditionthrough which fluid flows and a closed condition preventing fluid flow.In some examples, the valve 54 may be configured to facilitate flowcommunication or prevent flow communication between the fuel source 22and the GTE 20. For example, the valve 54 may be configured to change tothe closed condition to prevent flow of fuel to the corresponding GTE20, for example, to cease operation of the GTE 20 and/or during testingrelated to portions of the fuel delivery system 20.

As shown in FIGS. 1, 2A, 2B, and 3, some examples, of the fuel lineconnection assembly 14 may also include a sensor 56 disposed in themanifold line 32 (e.g., upstream relative to the distribution line 52)or the distribution line 52 and configured to generate a signalindicative of pressure associated with flow of fuel to the GTE 20 of therespective hydraulic fracturing unit 12. The sensor 56 may include anytransducer configured to generate a signal indicative of pressure in themanifold line 32 and/or the distribution line 52. As shown in FIG. 1,some examples of the fuel line connection assembly 14 may include apressure gauge 58 in flow communication with the manifold line 32downstream of the distribution line 52, for example, configured toprovide an indication of the pressure in the manifold line 32, forexample, for an operator of the hydraulic fracturing system 16. Thepressure gauge 58 may be any type of gauge configured to generate anindication of the pressure in the manifold line 32 downstream of thedistribution line 52. In some examples, the indication of pressure maybe viewed at a location remote from the manifold line 32, for example,at an operations console associated with the hydraulic fracturingoperation.

As shown in FIGS. 1, 2A, and 2B, the fuel line connection assembly 14may also include a filter 60 disposed in the distribution line 52between the manifold line 32 and the GTE 20 and configured to filter oneor more of particulates or liquids from fuel in flow communication withthe GTE 20. For example, as shown in FIG. 3, the filter 60 may include afirst filter 60 a configured to remove particulates from fuel suppliedto the GTE 20 and a second filter 60 b (e.g., a coalescing filter)configured to remove liquids from the fuel line connection assembly 14before fuel reaches the GTE 20. This may improve performance of the GTE20 and/or reduce maintenance and/or damage to the GTE 20 due tocontaminants in the fuel.

As shown in FIG. 1, some examples of the fuel line connection assembly14 may also include a sensor 62 disposed in the distribution line 52between the filter 60 and the GTE 20 of the respective hydraulicfracturing unit 12. The sensor 62 may be configured to generate a signalindicative of pressure associated with flow of fuel between the filter60 and the GTE 20. The sensor 56 and/or the sensor 62, upstream anddownstream, respectively, of the filter 60, may be used to determine apressure differential across the filter 60, which, if higher than apredetermined pressure, may be an indication that the filter 60 isinhibiting fuel flow through the filter 60, which may be an indicationthat the filter 60 should be cleaned, serviced, and/or replaced.

In some examples, the fuel line connection assembly 14 may be configuredto facilitate testing for leaks in at least a portion of the fueldelivery system 10 according to some embodiments of the disclosure. Forexample, as shown in FIGS. 1, 2A, 2B, and 3, the fuel line connectionassembly 14 may be configured to perform a pressure test to identifyleaks in at least a portion of the fuel delivery system 10. For example,the valve 54 may be a first valve 54, and the fuel line connectionassembly 14 may further include a second valve 64 disposed in thedistribution line 52 and configured to change between an open conditionthrough which fluid flows and a closed condition preventing fluid flow.The second valve 64 may be configured facilitate flow communication orprevent flow communication between the filter 60 and the GTE 20 of therespective hydraulic fracturing unit 12. The fuel line connectionassembly 14 may also include a test line 66 in flow communication withthe distribution line 52 between the filter 60 and the GTE 20 andconfigured to provide flow communication between a pressure source 68and the filter 60. In some examples, the fuel line connection assembly14 may also include a third valve 70 disposed in the test line 66 andconfigured to change between an open condition through which fluid flowsand a closed condition preventing fluid flow. The third valve 70 may beconfigured to facilitate flow communication or prevent flowcommunication between the pressure source 68 and the filter 60. In someexamples, the fuel line connection assembly 14 may further include afourth valve 72 disposed between the pressure source 68 and the filter60 and configured to change between an open condition through whichfluid flows and a closed condition preventing fluid flow. The fourthvalve 72 may be configured to release pressure in the test line 66between the pressure source 68 and the third valve 70, for example asdisclosed herein. One or more of the first valve 54, the second valve64, the third valve 70, or the fourth valve 72 may be a ball valve,although other types of valves are contemplated.

As shown in FIGS. 1, 2A, 2B, and 3, the fuel line connection assembly 14may also include a controller 74 configured to facilitate pressuretesting at least a portion of the fuel delivery system 10 and incommunication with one or more of the sensors 56 and 62 configured togenerate signals indicative of pressure, one or more of the first valve54, the second valve 64, the third valve 70, or the fourth valve 72, andthe pressure source 68. In some examples, the controller 74 may beconfigured to cause operation of one or more of the first valve 54, thesecond valve 64, the third valve 70, or the fourth valve 72, and receiveone or more signals from one or more of the sensors 56 and 62. Based atleast in part on the one or more signals, the controller 74 may beconfigured to determine the presence of a leak in at least a portion ofthe fuel delivery system 14 and/or the fuel line connection assembly 14,for example, semi- or fully-autonomously.

For example, as shown in FIG. 3, the fuel line connection assembly 14may include one or more actuators connected respectively to one or moreof the first valve 54, the second valve 64, the third valve 70, or thefourth valve 72 and configured cause one or more of the first valve 54,the second valve 64, the third valve 70, or the fourth valve 72 tochange conditions, for example, between an open condition and a closedcondition. As shown, a first actuator 76, a second actuator 78, a thirdactuator 80, and a fourth actuator 82 are respectively connected to thefirst valve 54, the second valve 64, the third valve 70, and the fourthvalve 72, and are configured to control the condition of the respectivevalve. As explained below, by coordinated activation of the firstactuator 76, second actuator 78, third actuator 80, and/or fourthactuator 82, and in some examples, control of the pressure source 68,the controller 74 may be configured to pressure test at least a portionof the fuel delivery system 14 and/or one or more of the fuel lineconnection assemblies 14 of the fuel delivery system 10, for example, toidentify leaks in at least a portion of the fuel delivery system 14,including one or more of the fuel line connection assemblies 14 of thefuel delivery system 10.

For example, FIG. 2A is a schematic view of an example fuel lineconnection assembly 14 in an example first condition for operation ofthe GTE 20 according to embodiments of the disclosure. As shown in FIG.2A, the first valve 54 and the second valve 64 are in the opencondition, such that fuel from the fuel source 22 flows via the fuelline 42, into the inlet end 34 of the manifold line 32 of the fuel lineconnection assembly 14, into the distribution line 52, through the firstvalve 54, through the filter 60, and through the second valve 64 to theGTE 20 for combustion to drive the pump 18 connected to the GTE 20. Asshown in FIG. 2A, the third valve 70 and the fourth valve 72 are in theclosed condition preventing fuel flow through those valves and/orpreventing pressure from the pressure source 68 from entering the fuelline connection assembly 14 through the third valve 70. In someexamples, the controller 74 may be configured to communicate with thefirst actuator 76, second actuator 78, third actuator 80, and/or fourthactuator 82 (see FIG. 3) to cause the respective valves to have theabove-noted conditions (e.g., open or closed).

FIG. 2B is a schematic view of the example fuel line connection assembly14 shown in FIG. 2A in an example second condition during a portion ofan example pressure testing procedure. As shown in FIG. 2B, to perform apressure test according to some embodiments of the disclosure, thecontroller 74 may be configured to cause the first valve 54 to be in theopen condition, cause the second valve 64 to be in the closed condition,cause the third valve 70 to be in the open condition, and cause thepressure source 68 to increase pressure in one or more of thedistribution line 52 or the manifold line 32. The controller 74 may befurther configured to determine the presence of a leak in the fuel lineconnection assembly 14 based at least in part on signals indicative ofpressure received from the sensor 62 between the pressure source 68 andthe filter 60 and/or the sensor 56 between the filter 60 and the fuelsource 22. For example, as explained in more detail herein with respectto FIG. 8, the controller 74 may be configured to cause (or allow) thepressure source 68 to cause an increase in pressure (or at least attemptto cause an increase in pressure) in the fuel line connection assembly14 and/or at least portions of the fuel delivery system 10. Depending atleast in part on whether a threshold pressure in the fuel lineconnection system 14 and/or the fuel delivery system 10 can be achieved,how quickly the threshold pressure is achieved, and/or once thethreshold pressure is achieved, how long and/or how much of thethreshold pressure is maintained, the controller 74 may be configured todetermine whether a leak in the fuel line connection assembly 14 and/orthe fuel delivery system 10 exists, and generate a signal indicative ofthe leak. In some examples, increasing pressure via the pressure source68 in at least a portion of the fuel delivery system 10 and/or fuel lineconnection assembly 14 may include activating a compressor in flowcommunication with at least a portion of the fuel delivery system 10and/or fuel line connection assembly 14 through the third valve 70and/or opening a valve of a pressurized cylinder in flow communicationwith at least a portion of the fuel delivery system 10 and/or the fuelline connection assembly 14 through the third valve 70. In someexamples, the pressure source 68 may include a cascade gas system, andin some examples, the pressurized gas may include nitrogen, argon, neon,helium, krypton, xenon, radon, and/or carbon dioxide, although othergases are contemplated. In some examples, the controller 74 may includeone or more industrial control systems (ICS), such as, for example,supervisory control and data acquisition (SCADA) systems, distributedcontrol systems (DCS), micro controllers, and/or programmable logiccontrollers (PLCs).

In some examples, once the testing is complete, or in order to cease thetesting, the controller 74 may be configured to cause the third valve 70to change from the open condition to the closed condition, for example,via activation of the third actuator 80, and cause the fourth valve 72to change from the closed condition to the open condition, for example,via activation of the fourth actuator 82, to thereby close-off thepressure source 68 and/or bleed any remaining excess pressure betweenthe pressure source 68 and the third valve 70. The controller 74 mayalso cause the second valve 64 to return to the open condition, forexample, via activation of the second actuator 78, and/or ensure thatthe first valve 54 remains in the open condition (see FIG. 2A), therebycausing the fuel delivery system 10 and/or the fuel line connectionassembly 14 to be in a condition to supply fuel from the fuel source 22for operation of the GTE 20.

FIG. 4 is a schematic diagram showing an example fuel delivery system 10for supplying fuel to a plurality of hydraulic fracturing units 12according to embodiments of the disclosure. As shown in FIG. 4, a firsthydraulic fracturing unit 12 a may be in flow communication with thefuel source 22 via the fuel line 42 (e.g., via a first fuel line 42 a).The inlet coupling 40 of the first hydraulic fracturing unit 12 a may becoupled to the fuel line 42 a. The outlet coupling 44 for the firsthydraulic fracturing unit 12 a may be coupled to an inlet coupling of amanifold line of a second hydraulic fracturing unit 12 b. Similarly, theoutlet coupling of the second hydraulic fracturing unit 12 b may becoupled to the inlet coupling of a manifold line of a third hydraulicfracturing unit 12 c. The outlet coupling of the manifold line of thethird hydraulic fracturing unit 12 c may be coupled to an inlet couplingof a manifold line of a fourth hydraulic fracturing unit 12 d.

In the example shown, the first through fourth hydraulic fracturingunits 12 a through 12 d may make up a first bank 46 of the hydraulicfracturing units 12, and fifth through eighth hydraulic fracturing units12 e through 12 h may make up a second bank 48 of the hydraulicfracturing units 12. In some examples, for example as shown in FIG. 1, afifth hydraulic fracturing unit 12 e may be in flow communication withthe fuel source 22 via the fuel line 42 (e.g., via a second fuel line 42b). The inlet coupling of the fifth hydraulic fracturing unit 12 e maybe coupled to the fuel line 42 b. The outlet coupling for the fifthhydraulic fracturing unit 12 e may be coupled to an inlet coupling of amanifold line of a sixth hydraulic fracturing unit 12 f. Similarly, theoutlet coupling of the sixth hydraulic fracturing unit 12 f may becoupled to an inlet coupling of a manifold line of a seventh hydraulicfracturing unit 12 g. The outlet coupling of the manifold line of theseventh hydraulic fracturing unit 12 g may be coupled to an inletcoupling of a manifold line of an eighth hydraulic fracturing unit 12 h.The example fuel delivery system 10 shown in FIG. 4 may sometimes bereferred to as a “daisy-chain” arrangement.

FIG. 5 is a schematic diagram showing another example fuel deliverysystem 10 for supplying fuel to a plurality of hydraulic fracturingunits 12 according to embodiments of the disclosure. As shown in FIG. 5,the inlet end 34 of the manifold line 32 of the first hydraulicfracturing unit 12 a is connected to an outlet 84 of a main fuel line 86a, which is connected to a hub 88 (e.g., a fuel hub). Rather than beingconnected to an inlet end of another manifold line of the secondhydraulic fracturing unit 12 b as in FIG. 4, the outlet end 36 of themanifold line 32 of the first hydraulic fracturing unit 12 a isconnected to a blocking device (not shown) configured to prevent flowfrom the outlet end 36 of the manifold line 32 of the first hydraulicfracturing unit 12 a. The inlet ends of the respective manifold lines ofthe second hydraulic fracturing unit 12 b, the third hydraulicfracturing unit 12 c, the fourth hydraulic fracturing unit 12 d, thefifth hydraulic fracturing unit 12 e, the sixth hydraulic fracturingunit 12 f, the seventh hydraulic fracturing unit 12 g, and the eighthhydraulic fracturing unit 12 h (and/or more hydraulic fracturing units)are connected to the hub 88 via respective main fuel lines 86 b, 86 c,86 d, 86 e, 86 f, 86 g, and 86 h. The outlet ends of the manifold linesof the second through eighth hydraulic fracturing units 12 b through 12h are each connected to a blocking device (not shown) configured toprevent flow from the outlet ends of the respective manifold lines. Theexample fuel delivery system 10 shown in FIG. 5 may sometimes bereferred to as a “hub and spoke” arrangement.

FIG. 6 is a schematic diagram showing a further example fuel deliverysystem 10 for supplying fuel to a plurality of hydraulic fracturingunits 12 according to embodiments of the disclosure. The example fueldelivery system shown in FIG. 6 is similar to the example fuel deliverysystem shown in FIG. 5, except that the fuel delivery system 10 includestwo hubs 90 a and 90 b (e.g., fuel hubs). A first one of the hubs 90 ais connected to the fuel source 22 via a first fuel line 42, and asecond hub 90 b is connected to the fuel source 22 via a second fuelline 42 b. The first hub 90 a may supply fuel to one or more (e.g.,each) of the GTEs 20 of the first bank 46 of hydraulic fracturing units12, and the second hub 90 b may supply fuel to one or more (e.g., each)of the GTEs 20 of the second bank 48 of hydraulic fracturing units 12.More than two hubs are contemplated. The example fuel delivery system 10shown in FIG. 5 may sometimes be referred to as a “hub and spoke”arrangement, with two or more hubs.

FIG. 7 is a schematic diagram showing another example fuel deliverysystem 10 for supplying fuel to a plurality of hydraulic fracturingunits 12 according to embodiments of the disclosure. The example fueldelivery system 10 shown in FIG. 7 includes a fuel manifold 92, and theexample fuel manifold 92 receives fuel from the fuel source 22 via afirst fuel line 42 a and a second fuel line 42 b, with the first fuelline 42 a supplying fuel to the GTEs 20 of the first bank 46 ofhydraulic fracturing units 12, and the second fuel line 42 b supplyingfuel for the GTEs 20 of the second bank 48 of hydraulic fracturing units12. In some examples, the inlet end 34 of the manifold line 32 of thefirst hydraulic fracturing unit 12 a is connected to a respective outletof the fuel manifold 92 (e.g., a first bank 94 a of the fuel manifold 92the or main fuel line). In the example shown, the outlet end 36 of themanifold line 32 of the first hydraulic fracturing unit 12 a isconnected to a blocking device (not shown) configured to prevent flowfrom the outlet end 36 of the manifold line 32 of the first hydraulicfracturing unit 12 a. The inlet ends of the respective manifold lines ofthe second hydraulic fracturing unit 12 b, the third hydraulicfracturing unit 12 c, and the fourth hydraulic fracturing unit 12 d areconnected to the first bank 94 a of the fuel manifold 92. The outletends of the manifold lines of the second through fourth hydraulicfracturing units 12 b through 12 d are each connected to a blockingdevice (not shown) configured to prevent flow from the outlet ends ofthe respective manifold lines. In the example shown in FIG. 7, the inletends of the respective manifold lines of the fifth hydraulic fracturingunit 12 e through the eighth hydraulic fracturing unit 12 h areconnected to respective outlets of the fuel manifold 92 (e.g., a secondbank 94 b of the fuel manifold 92 or main fuel line). In the exampleshown, the outlet ends of the respective manifold lines of the fifththrough eighth hydraulic fracturing units 12 e through 12 h are eachconnected to a blocking device (not shown) configured to prevent flowfrom the outlet ends of the respective manifold lines of the fifththrough eighth hydraulic fracturing units 12 e through 12 h. In someexamples, the fuel manifold 92 may be connected to a trailer forportability. The example fuel delivery system 10 shown in FIG. 7 maysometimes be referred to as a “combination” arrangement.

In some examples, the configuration of the fuel line connectionassemblies 14 may facilitate arranging the hydraulic fracturing units in(1) a “daisy-chain” arrangement, in which fuel passes through each ofmanifold lines 32 in a series-type arrangement, (2) a “hub and spoke”arrangement, in which an inlet end of each of the manifold lines 32 isconnected to a fuel line from a fuel hub or the fuel source and flowfrom an outlet end is prevented, or (3) a “combination” arrangement,such as the example shown in FI G. 7, which may include connection ofthe inlet ends of the manifold lines 32 to a fuel manifold 92. Differentarrangements may be desirable depending on a number of factorsassociated with the fracturing operation, and the flexibility ofarrangements provided by at least some examples of the fuel deliverysystem 10 may reduce the need for multiple sets of parts to achieve eachof the different arrangements. In addition, the couplings provided bythe manifold lines 32, at least according to some embodiments, mayreduce the time and complexity associated with setting-up and/orbreaking-down the hydraulic fracturing system 16. In some examples, thenumber and/or types of tools required to set-up and/or break-down thehydraulic fracturing system 16 may also be reduced.

FIG. 8 is a block diagram of an example method 800 for pressure testingat least a portion of a fuel delivery system for supplying fuel from afuel source to a plurality of GTEs according to embodiments of thedisclosure, illustrated as a collection of blocks in a logical flowgraph, which represent a sequence of operations that may be implementedin hardware, software, or a combination thereof. In the context ofsoftware, the blocks represent computer-executable instructions storedon one or more computer-readable storage media that, when executed byone or more processors, perform the recited operations. Generally,computer-executable instructions include routines, programs, objects,components, data structures, and the like that perform particularfunctions or implement particular data types. The order in which theoperations are described is not intended to be construed as alimitation, and any number of the described blocks can be combined inany order and/or in parallel to implement the methods.

FIG. 8 is a flow diagram of an example method 800 for pressure testingat least a portion of a fuel delivery system for supplying fuel from afuel source to a plurality of GTEs, for example, associated with pumpsin a hydraulic fracturing system, according to embodiments of thedisclosure. In some examples, the method 800 may be performed semi- orfully-autonomously, for example, via a controller. The method 800 may beutilized in association with various systems, such as, for example, theexample fuel delivery systems 10 shown in one or more of FIGS. 1, 2A,2B, 3-7, or 9-16.

The example method 800, at 802, may include causing a first valve to bein an open condition. The first valve may be configured to facilitateflow communication or prevent flow communication between a fuel sourceand a GTE of the plurality of GTEs. For example, a controller may beconfigured to communicate with an actuator to activate the actuator tocause the first valve to be in the open condition, so that flowcommunication exists between the GTE and the fuel source.

At 804, the example method 800 may further include causing a secondvalve to be in a closed condition. The second valve may be configured tofacilitate flow communication or prevent flow communication between afilter configured to filter one or more of particulates or liquids fromfuel and the GTE. For example, the controller may be configured tocommunicate with an actuator to activate the actuator to cause thesecond valve to be in the closed condition, so that flow communicationbetween the filter and the GTE is prevented. This may effectivelyisolate or close-off the GTE from flow communication with the fueldelivery system and/or the remainder fuel line connection assembly(e.g., with the distribution line).

At 806, the example method 800 may also include causing a third valve tobe in an open condition. The third valve may be configured to facilitateflow communication or prevent flow communication between a pressuresource and the filter. For example, the controller may be configured tocommunicate with an actuator to activate the actuator to cause the thirdvalve to be in the open condition, so that flow communication existsbetween the pressure source and the filter.

The example method 800, at 808, may further include increasing pressurevia the pressure source in the at least a portion of the fuel deliverysystem. For example, the controller may be configured to cause thepressure source to increase pressure (or at least attempt to increasepressure) in the fuel line connection assembly and/or the fuel deliverysystem, for example, to determine whether the fuel line connectionassembly and/or the fuel line delivery system is sufficiently leak-tightfor pressure to increase to, and/or hold, a predetermined or thresholdpressure for a period of time. In some examples, increasing pressure viathe pressure source may include activating a compressor in flowcommunication with the portion of the fuel line connection assemblyand/or the fuel delivery system, and/or opening a valve of a pressurizedcylinder in flow communication with the portion of the fuel lineconnection assembly and/or the fuel delivery system.

The example method 800, at 810, may also include initiating a timer. Insome examples, the controller may be configured to initiate a timer andcause the increase (or attempt to increase) the pressure until apredetermined time has elapsed.

At 812, the example method 800 may also include monitoring a signalindicative of pressure in the at least a portion of the fuel deliverysystem. For example, a pressure sensor in flow communication with thefuel line connection system and/or the fuel delivery system may generateone or more signals indicative of the pressure in the assembly and/orsystem, for example, and the controller may receive the one or moresignals and determine whether the pressure increases to thepredetermined or threshold pressure.

At 814, the example method 800 may further include, based at least inpart on the signal, determining whether the at least a portion of thefuel delivery system has a leak. For example, the controller may receivethe one or more signals from the sensor indicative of pressure in thefuel line connection assembly and/or the fuel delivery system and, basedat least in part on the one or more signals, determine whether a leakexists in the fuel line connection assembly and/or the fuel deliverysystem. In some examples, this determination may include comparing thepressure in at least a portion of the fuel delivery system at the end ofthe predetermined time to a predetermined pressure, and determiningwhether the portion of the fuel delivery system has a leak when thepressure in the portion of the fuel delivery system is less than thepredetermined pressure, or the portion of the fuel delivery system doesnot have a leak when the pressure in the at least a portion of the fueldelivery system is at least the predetermined pressure by the end of thepredetermined time. In some examples, if it has been determined that thepressure in the fuel delivery system has reached the predeterminedpressure, for example, prior to the end of the predetermined time, themethod may include initiating the timer, waiting for a secondpredetermined time to elapse, and comparing the pressure in the portionof the fuel delivery system at the second predetermined time to thepredetermined pressure. If the pressure in the fuel delivery systemremains above the predetermined pressure at the end of the secondpredetermined time, the controller may be configured to determine thatthe fuel line connection assembly and/or the fuel delivery system doesnot have a leak.

The example method 800, at 816, if it has been determined that the fueldelivery system has a leak, may also include generating a signalindicative of the leak. For example, if the controller determines thatthe fuel line connection assembly and/or the fuel delivery system has aleak, the controller may generate an alarm signal indicative of the leakthat may be received by personnel at the hydraulic fracturing site, sothat remedial measures may be performed. In some examples, the methodmay be configured to sequentially isolate fuel line connectionassemblies associated with respective hydraulic fracturing units andperform a pressure test on each one of the fuel line connectionassemblies associated with each of the hydraulic fracturing units. Forexample, the controller may be configured to cause valves of fuel lineconnection assemblies to be in a closed condition, so that a fuel lineconnection assembly being tested can be isolated and the pressure testperformed for the isolated fuel line connection assembly. This processmay be repeated for one or more of the other fuel line connectionassemblies associated with respective hydraulic fracturing units.

The example method 800, at 818, if no leak has been determined at 814,may further include ceasing the pressure testing, for example, after oneor more of the predetermined times have elapsed and no leaks have beendetected by the controller. In addition, once a leak has been detected,for example, at 814, the method 800 may also include ceasing thepressure testing. This may include isolating the pressure source fromthe fuel line connection assembly and/or the fuel delivery system. Insome examples, this may include ceasing operation of a compressor,closing a valve on a pressure source, such as a high pressure tank, etc.

At 820, the example method 800 may include causing a fourth valve to bein an open condition. The fourth valve may be configured to releasepressure in the at least a portion of the fuel delivery system, such asthe fuel line connection assembly and/or the test line. The controllermay communicate with an actuator associated with the fourth valve tocause the fourth valve to be in the open condition, thereby releasingpressure increased during the pressure testing from the fuel lineconnection assembly and/or the fuel delivery system.

At 822, the example method 800 may further include causing the thirdvalve to be in the closed condition and causing the second valve to bein the open condition. For example, the controller may be configured tocommunicate with actuators associated with the second and third valvesand cause the second valve to be in the open condition so that fuel fromthe fuel source may be supplied to the GTE and cause the third valve tobe in the closed condition to prevent fuel from passing to the test lineand/or the pressure source during operation of the GTE.

In some examples, once a pressure test has been initiated, the firstvalve will be caused to be in the open condition for example, to allowpressure from the pressure source to fill at least a portion of the fueldelivery system (e.g., the entire fuel delivery system, including one ormore fuel lines from the fuel source). The second valve will be causedto be in the closed condition and isolate the GTE from the fuel deliverysystem. The third valve will be caused to be in the open condition toallow pressure from the pressure source the fill the fuel deliverysystem and build pressure therein. The fourth valve will be caused to bein the closed condition to allow pressure to build (or attempt to build)in the fuel delivery system.

Once the first, second, third, and fourth valves are in the above-notedconditions, the pressure source will be activated to build (or attemptto build) pressure in the fuel delivery system. The sensors willgenerate signals indicative of the pressure in the fuel delivery system,which will be received by the controller. The controller will initiate atimer, and the pressure source will attempt to increase the pressure inthe fuel delivery system to a predetermined threshold pressure for apredetermined time. The threshold pressure and/or the predetermined timemay be set by an operator and/or automatically controlled via thecontroller according to a program. If the pressure source is unable tocause the pressure in the fuel delivery system to achieve the pressurethreshold before the predetermined time has elapsed, the controller maycause the pressure source to discontinue attempting to increase thepressure in the fuel delivery system (e.g., the controller will ceaseoperation of a compressor serving as the pressure source). Thecontroller may also generate a signal and/or an alarm to notify anoperator of a possible leak in the fuel delivery system.

If, however, the pressure in the fuel delivery system reaches thepredetermine threshold pressure, the controller may cause the pressuresource to discontinue attempting to increase the pressure in the fueldelivery system. The controller may also initiate a new timer andmonitor the pressure in the fuel delivery system for a secondpredetermined time (e.g., five minutes). If the pressure in the fueldelivery system remains stable for the duration of the secondpredetermined time, the controller may determine that no leaks arepresent in the fuel delivery system, and the pressure test may be deemedsuccessful. If the pressure drops, for example, greater than apredetermined rate (e.g., greater than 5% during the secondpredetermined time), the controller may be configured to generate asignal and/or an alarm to notify an operator of a possible leak in thefuel delivery system.

At the end of the pressure test, the controller (and/or the operator)may bleed pressure from the fuel delivery system, causing the fourthvalve to change to the open condition to vent the pressure from the fueldelivery system. After pressure has been bled from the fuel deliverysystem, the controller may cause the first, second, third, and fourthvalves to change to the condition consistent with operation of thehydraulic fracturing system, for example, such that the first valve isin the open condition to allow fuel to flow from the pressure source tothe filter, the second valve is in the open condition to allow fuel toflow from the filter to the GTE, such that the third valve is in theclosed condition to prevent fuel from flowing to the pressure source orto the fourth valve, and such that the fourth valve is in the closedcondition, so that if another pressure test is commenced, the fourthvalve will prevent bleeding of the pressure from the pressure source.

It should be appreciated that subject matter presented herein may beimplemented as a computer process, a computer-controlled apparatus, acomputing system, or an article of manufacture, such as acomputer-readable storage medium. While the subject matter describedherein is presented in the general context of program modules thatexecute on one or more computing devices, those skilled in the art willrecognize that other implementations may be performed in combinationwith other types of program modules. Generally, program modules includeroutines, programs, components, data structures, and other types ofstructures that perform particular tasks or implement particularabstract data types.

Those skilled in the art will also appreciate that aspects of thesubject matter described herein may be practiced on or in conjunctionwith other computer system configurations beyond those described herein,including multiprocessor systems, microprocessor-based or programmableconsumer electronics, minicomputers, mainframe computers, handheldcomputers, mobile telephone devices, tablet computing devices,special-purposed hardware devices, network appliances, and the like.

FIG. 9 is a schematic diagram showing a portion of an example hydraulicfracturing system 16 including an example system 100 for supplying fuel,enabling communications, and conveying electric power associated withoperation of a plurality of hydraulic fracturing units 12 according toembodiments of the disclosure. The example system 100 shown in FIG. 9may sometimes be referred to as a “daisy-chain” arrangement. In theexample shown in FIG. 9, the system 100 includes a main fuel line 86configured to supply fuel from a fuel source 22 to the plurality ofhydraulic fracturing units 12. Each of the example hydraulic fracturingunits 12 includes a chassis 30 (e.g., including a trailer and/or a truckbody), a pump 18 connected to the chassis 30, and a GTE 20 connected tothe chassis 30 and configured to convert fuel into a power output foroperating the pump 18. In the example shown, the hydraulic fracturingunits 12 are arranged into a first bank 46 of hydraulic fracturing units12 and a second bank 48 of hydraulic fracturing units 12, and the mainfuel line 86 includes a first main fuel line 86 a configured to supplyfuel to the first bank 46 of hydraulic fracturing units 12 and a secondmain fuel line 86 b configured to supply fuel to the second bank 48 ofthe hydraulic fracturing units.

In the example system 100 shown in in FIG. 9, a fuel line connectionassembly 14 is provided for each of the hydraulic fracturing units tosupply fuel from the fuel source 22 to each of the GTEs 20 of therespective hydraulic fracturing units 12. The respective fuel lineconnection assemblies 14 may include a manifold line 32 defining aninlet end 34, an outlet end 36, and a flow path 38 for fuel extendingbetween the inlet end 34 and the outlet end 36 (see, e.g., FIGS. 1, 2A,2B, and 3). The manifold line 32 may be configured to provide at least aportion of a flow path for supplying fuel to a first GTE 20 of therespective hydraulic fracturing unit 12. One or more of the fuel lineconnection assemblies 14 may be configured to provide flow communicationbetween the main fuel line 86 or another GTE 20 (relative to the firstGTE 20 associated with the fuel line connection assembly 14) of anotherhydraulic fracturing unit 12 upstream of the first GTE 20, and anotheradditional GTE 20 of another additional hydraulic fracturing unit 12downstream of the first GTE 20.

For example, as shown in FIG. 9, the fuel line connection assembly 14associated with a first GTE 20 a of a respective first hydraulicfracturing unit 12 a includes a first manifold line 32 a having an inletend configured to be in flow communication with the first main fuel line86 a and an outlet end configured to be in flow communication with aninlet end of a manifold line 32 b of a second hydraulic fracturing unit12 b downstream of the first hydraulic fracturing unit 12 a. The fuelline connection assembly 14 associated with a second GTE 20 b of therespective second hydraulic fracturing unit 12 b includes the secondmanifold line 32 b having the inlet end configured to be in flowcommunication with the outlet end of the first manifold line 32 a of thefirst hydraulic fracturing unit 12 a upstream of the second hydraulicfracturing unit 12 b, and an outlet end configured to be in flowcommunication with an inlet end of a manifold line 32 c of a thirdhydraulic fracturing unit 12 c downstream of the second hydraulicfracturing unit 12 b. In some examples, this pattern may be repeatedthroughout the first bank 46 of hydraulic fracturing units 12 a through12 d, and again throughout the second bank 48 of hydraulic fracturingunits 12 e though 12 h.

As shown in FIG. 9, in some examples, fuel that reaches the end of thefirst bank 46 of the hydraulic fracturing units 12 remote from the fuelsource 22 and/or fuel that reaches the end of the second bank 48 of thehydraulic fracturing units 12 remote from the fuel source 22 may becombined and/or transferred between the first bank 46 and the secondbank 48, for example, via a transfer line 50 configured to provide flowcommunication between the first bank 46 and the second bank 48. Forexample, unused fuel supplied to either of the first bank 46 or thesecond bank 48 of hydraulic fracturing units 12 may be passed to theother bank of the two banks via the transfer line 50, thereby sharingfuel between the banks 46 and 48.

As shown in FIG. 9, the system 100 may also include, for one or more(e.g., each) of the hydraulic fracturing units 12, a communicationscable assembly 102 including a length of communications cable 104connected to a respective one of the hydraulic fracturing units 12 andconfigured to enable data communications between the respectivehydraulic fracturing unit 12 and a data center 106 remote from therespective hydraulic fracturing unit 12 or one or more additionalhydraulic fracturing units 12.

For example, as shown FIG. 9, a data center communications cable 108 mayprovide a communications link between the data center 106 and a firstone of the hydraulic fracturing units 12. The hydraulic fracturing unit12 may include a length of communications cable 104 that extends to anext one of the hydraulic fracturing units 12, and that hydraulicfracturing unit 12 may include a length of communications cable 104 thatextends to a next one of the hydraulic fracturing units 12. In someexamples, each of the hydraulic fracturing units 12 may include a lengthof communications cable 104 for extending to a next one of the hydraulicfracturing units 12. In this example fashion, each of the hydraulicfracturing units 12 may be linked to one another and to the data center104. As shown in FIG. 9, in some examples, a last-in-line hydraulicfracturing unit 12 may include a length of communications cable 104 thatruns to the data center 106, thus resulting in a continuouscommunications link, by which one or more of the hydraulic fracturingunits 12 may be in communication with the data center 104. In someexamples, the data center 104 may be configured to transmitcommunications signals and/or receive communications signals, and thecommunications signals may include data indicative of operation of oneor more of the plurality of hydraulic fracturing units 12, including,for example, parameters associated with operation of the pumps 18 and/orthe GTEs 20, as well as additional data related to other parametersassociated with operation and/or testing of one or more of the hydraulicfracturing units 12.

In some examples, the communications cable 104 may include a first endconfigured to be connected to a first unit interface connected to arespective hydraulic fracturing unit 12. The length of communicationscable 104 may also include a second end configured to be connected to adata center interface of the data center 106 or a second unit interfaceconnected to another one of the hydraulic fracturing units 12. One ormore of the first end or the second end of the length of communicationscable 104 may include or be provided with a quick connecter configuredto be connected to one or more of the first unit interface or the datacenter interface, for example, as discussed herein with respect to FIG.18.

In some examples, the communications cable assembly 102 may also includea communications cable storage apparatus connected to the respectivehydraulic fracturing unit 12 and configured to store the length ofcommunications cable 104 when not in use and to facilitate deployment ofat least a portion of the length of communications cable 104 forconnection to the data center 106 or the another hydraulic fracturingunit 12. The communications cable storage apparatus may include a cablereel configured to be connected to the hydraulic fracturing unit 12and/or a cable support configured to be connected to the hydraulicfracturing unit 12 and to receive windings of at least a portion of thelength of communications cable 104.

As shown in FIG. 9, some examples of the system 100 may also include apower cable assembly 110 including a length of power cable 112 connectedto one or more (e.g., each) of the hydraulic fracturing units 12 andconfigured to convey electric power between the hydraulic fracturingunits 12 and a remote electrical power source or one or more additionalhydraulic fracturing units 12 of the hydraulic fracturing system 16. Forexample, as shown in FIG. 9, a length of power cable 112 is connected toeach of the hydraulic fracturing units 12, and each of the lengths ofpower cable 112 are configured to be connected to a next-in-linehydraulic fracturing unit 12. In some examples, the length of powercable 112 may extend from one hydraulic fracturing unit 12 to anotherhydraulic fracturing unit 12 other than a next-in-line hydraulicfracturing unit 12. One or more of the lengths of power cable 112 mayinclude a first end including a power plug configured to be received ina power socket, for example, as discussed herein with respect to FIG.19.

In some examples, one or more of the power cable assemblies 110 may alsoinclude a power cable storage apparatus configured to be connected tothe respective hydraulic fracturing unit 12. The power cable storageapparatus, in some examples, may be configured to store the length ofpower cable 112 when not in use and to facilitate deployment of at leasta portion of the length of power cable 112 for use.

As shown in FIG. 9, each of the hydraulic fracturing units 12 in theexample shown includes a length of power cable 112. In some suchexamples, each of the hydraulic fracturing units 12 is configured tosupply and/or generate its own electric power, for example, by operationof a generator connected to the GTE 20 and/or to another source ofmechanical power, such as another gas turbine engine or reciprocatingpiston engine (e.g., a diesel engine). In the example configurationshown in FIG. 9, the lengths of power cable 112 run between each of thehydraulic fracturing units 12, thus connecting all the hydraulicfracturing units 12 to one another, such that power may be shared amongat least some or all of the hydraulic fracturing units 12. Thus, if oneor more of the hydraulic fracturing units 12 is unable to generate itsown electric power or is unable to generate a sufficient amount ofelectric power to meet its operation requirements, electric power fromone or more of the remaining hydraulic fracturing units 12 may be usedto mitigate or overcome the electric power deficit. As shown additionallengths of power cable 114 may be included in the system 100 to supplyelectric power between the two banks 46 and 48 of the hydraulicfracturing units 12.

FIG. 10 is a schematic diagram showing another example system 100 forsupplying fuel, enabling communications, and conveying electric powerassociated with operation of a plurality of hydraulic fracturing units12 according to embodiments of the disclosure. The example system 100shown in FIG. 10 is similar to the example system 100 shown in FIG. 9,except that the example system 100 shown in FIG. 10 includes anelectrical power source 116 located remotely from each of the hydraulicfracturing units 12, for example, such that the electrical power source116 is not mechanically connected directly to the chassis 30 of one ormore of the hydraulic fracturing units 12. In some examples, theelectrical power source 116 may include one or more of one or more powergeneration devices or one or more batteries. For example, the electricalpower source 116 may include one or more gensets (e.g., including aninternal combustion engine-driven electrical generator) and/or one ormore electric power storage devices, such as, for example, one or morebatteries.

As shown in FIG. 10, the electrical power source 116 may be electricallycoupled to one or more of the first bank 46 or the second bank 48 of thehydraulic fracturing units 12 via an additional length of power cable114, and in some examples, the first bank 46 and the second bank 48 ofhydraulic fracturing units 12 may be, electrically coupled to oneanother via additional lengths of power cable 114. In at least some suchexamples, even if one or more of the hydraulic fracturing units 12 lackselectric power, electric power may be supplied to that particularhydraulic fracturing unit 12 via power cables 104 and/or 114, therebyproviding an ability to continue operations of the hydraulic fracturingunits 12.

FIG. 11 is a schematic diagram showing a further example system 100 forsupplying fuel, enabling communications, and conveying electric powerassociated with operation of a plurality of hydraulic fracturing units12 according to embodiments of the disclosure. The example system 100shown in FIG. 11 may sometimes be referred to as a “hub and spoke”arrangement. In the example shown in FIG. 11, the system 100 includes afuel source 22 for supplying fuel to the plurality of hydraulicfracturing units 12, and a fuel hub 118 for distributing the fuel fromthe fuel source 22 to each of the plurality of hydraulic fracturingunits 12. For example, the fuel hub 118 may be in flow communicationwith the fuel source 22 via the main fuel lines 86 a and 86 b, and thefuel hub 118 may be in flow communication with each of the fuel lineconnection assemblies 14 of each of the respective hydraulic fracturingunits 12 (see, e.g., FIGS. 1, 2A, 2B, and 3). In the example shown, theinlet end 34 of each of the manifold lines 32 of the each of thehydraulic fracturing units 12 is connected to an outlet of the main fuelline 86, for example, via the fuel hub 118. In some such examples, theoutlet end 36 of each of the manifold lines 32 of the respectivehydraulic fracturing units 12 is connected to a blocking deviceconfigured to prevent flow from the outlet end 36 of the manifold line32.

In the example shown in FIG. 11, the system 100 includes a data center106 located remotely from each of the hydraulic fracturing units 12(e.g., the data center 106 is not mechanically connected to the chassis30 of any of the hydraulic fracturing units 12). The data center 106 iscommunicatively connected to a communications hub 120, and each of thehydraulic fracturing units 12 is communicatively connected to thecommunications hub 120 by their respective communications cableassemblies 102, including the respective communications cables 104.

In the example shown in FIG. 11, the system 100 also includes a powerhub 122 electrically connected to each of the hydraulic fracturing units12 via the respective power cable assemblies 110, including therespective power cables 112. In some examples, the power hub 122 may beconfigured to supply electric power to any of the hydraulic fracturingunits 12 unable to supply its own electric power and/or unable toprovide a sufficient amount of its own electric power. For example, atleast some of the hydraulic fracturing units 12 may be configured togenerate electric power, for example, via one or more genets mounted tothe respective chassis 30 of the respective hydraulic fracturing unit12. Any excess electric power generated by one or more of the hydraulicfracturing units 12 may be electrically communicated to the power hub122 via the respective power cable assembly 110. Such excess power maybe electrically communicated from the power hub 122 to any of thehydraulic fracturing units 12 lacking sufficient electric power via therespective power cable assembly 110.

FIG. 12 is a schematic diagram showing another example system 100 forsupplying fuel, enabling communications, and conveying electric powerassociated with operation of a plurality of hydraulic fracturing units12 according to embodiments of the disclosure. The example system 100shown in FIG. 12 is similar to the example system 100 shown in FIG. 11,except that it includes a first fuel hub 118 a and a second fuel hub 118b, a first communications hub 120 a and a second communications hub 120b, and a first power hub 122 a and a second power hub 122 b, eachrespectively supplying fuel, communications, and electric power, to thefirst bank 46 of hydraulic fracturing units 12 and the second bank 48 ofthe hydraulic fracturing units 12.

For example, a first main fuel line 86 a may provide flow communicationfrom the fuel source 22 to the first fuel hub 118 a, and the second mainfuel line 86 b may provide flow communication from the fuel source 22 tothe second fuel hub 118 b. The first and second fuel hubs 118 a and 118b may respectively supply fuel to each of the manifold lines 32 of therespective hydraulic fracturing units 12 of each of the first and secondbanks 46 and 48 of the hydraulic fracturing units 12. The firstcommunications hub 120 a may be communicatively connected to each of thehydraulic fracturing units 12 of the first bank 46, and the secondcommunications hub 120 b may be communicatively connected to each of thehydraulic fracturing units 12 of the second bank 48, for example, viathe communications cable assembly 102 of each of the hydraulicfracturing units 12. In some examples, one or more of the firstcommunications hub 120 a or the second communications hub 120 b may becommunicatively connected to the data center 104, for example, as shownin FIG. 12. In some examples, the first and second communications hubs120 a and 120 b may be communicatively linked via an intermediatecommunications cable 124, for example, as shown in FIG. 12.

As shown in FIG. 12, each of the first and second power hubs 122 a and122 b may be electrically connected to the first bank 46 and second bank48, respectively, of the hydraulic fracturing units 12, for example, viathe respective power cable assemblies 110 of each of the hydraulicfracturing units 12. As shown in FIG. 12, in some examples, the firstpower hub 122 a and the second power hub 122 b may be electricallyconnected to one another via an intermediate power cable 126. In someexamples, the first and second power hubs 122 a and 122 b may beconfigured to supply electric power to any of the hydraulic fracturingunits 12 unable to supply its own electric power and/or unable toprovide a sufficient amount of its own electric power. For example, atleast some of the hydraulic fracturing units 12 may be configured togenerate electric power, for example, via one or more genets mounted tothe respective chassis 30 of the respective hydraulic fracturing unit12. Any excess electric power generated by one or more of the hydraulicfracturing units 12 may be electrically communicated to the first andsecond power hubs 122 a and 122 b via the respective power cableassembly 110. Such excess power may be electrically communicated fromone or more of the first and second power hubs 122 a and/or 122 b to anyof the hydraulic fracturing units 12 lacking sufficient electric powervia the respective power cable assembly 110.

FIG. 13 is a schematic diagram showing a further example system 100 forsupplying fuel, enabling communications, and conveying electric powerassociated with operation of a plurality of hydraulic fracturing units12 according to embodiments of the disclosure. The example system shownin FIG. 13 is similar to the example system 100 shown in FIG. 11, exceptthat the system 100 shown in FIG. 13 includes an electrical power source116 located remote from the hydraulic fracturing units 12 (e.g., notmechanically connected to any of the chassis 30 of the hydraulicfracturing units 12). The electrical power source 116 may beelectrically connected to the power hub 122 via an additional length ofpower cable 114, and the power hub 122 may be electrically connected toeach of hydraulic fracturing units 12 via their respective power cableassemblies 110, for example, as shown in FIG. 13.

FIG. 14 is a schematic diagram showing another example system 100 forsupplying fuel, enabling communications, and conveying electric powerassociated with operation of a plurality of hydraulic fracturing units12 according to embodiments of the disclosure. The example system 100shown in FIG. 14 is similar to the example system 100 shown in FIG. 12,except that the system 100 shown in FIG. 14 includes an electrical powersource 116 located remote from the hydraulic fracturing units 12 (e.g.,not mechanically connected to any of the chassis 30 of the hydraulicfracturing units 12). The electrical power source 116 may beelectrically connected to the first power hub power hub 122 a via afirst additional length of power cable 114 a, and connected to thesecond power hub power hub 122 b via a second additional length of powercable 114 b. The first and second power hubs 122 a and 122 b may beelectrically connected to each of hydraulic fracturing units 12 viatheir respective power cable assemblies 110, for example, as shown inFIG. 14.

FIG. 15 is a schematic diagram showing a further example system 100 forsupplying fuel, enabling communications, and conveying electric powerassociated with operation of a plurality of hydraulic fracturing units12 according to embodiments of the disclosure. In the example system 100shown in FIG. 15, the system 100 may include a main fuel manifold 128 inflow communication with the fuel supply 22 via a first main fuel line 86a and a second main fuel line 86 b. In some examples, the main fuelmanifold 128 may be mounted on a trailer or a truck body for portability(e.g., on a high-pressure iron manifold trailer) or supported by theground. In the example shown, the main fuel manifold 128 includes afirst fuel line 130 a and a second fuel line 130 b running along thelength of the main fuel manifold 128. In some examples, each of thefirst and second fuel lines 130 a and 130 b may include a plurality ofvalves, each of which may be in flow communication with a respectivemanifold line 32 of each of the hydraulic fracturing units 12. The firstfuel line 130 a may be configured to supply fuel to the first bank 46 ofhydraulic fracturing units 12, and the second fuel line 130 b may beconfigured to supply fuel to the second bank 48 of the hydraulicfracturing units 12, for example, via the respective manifold lines 32of the respective hydraulic fracturing units 12. In some examples, thefirst fuel line 130 a and the second fuel line 130 b may be in flowcommunication with one another via an intermediate fuel line 132, which,in some examples, may assist with equalizing pressure and/or volumebetween the first fuel line 130 a and the second fuel line 130 b.

The example system 100 shown in FIG. 15 also includes a communicationsharness 134 in communication with the data center 106, for example, viaa first communications cable 136 a and a second communications cable 136b. In some examples, the communications harness 134 may be mounted on atrailer or a truck body for portability (e.g., on a high-pressure ironmanifold trailer) or supported by the ground. In some examples, thecommunications harness 134 may include a plurality of connection pointsalong its length configured to facilitate connection to a communicationscable 104 from each of the respective hydraulic fracturing units 12 toprovide a communications link between each of the hydraulic fracturingunits 12 and the data center 106. As shown, some examples of thecommunications harness 134 may include a first communications harness134 a and a second communications harness 134 b configured torespectively provide communications links with the first bank 46 and thesecond bank 48 of the hydraulic fracturing units 12.

As shown in FIG. 15, the example system 100 also includes a powerharness 138 in electrical communication with the plurality of powercables 112 of the respective hydraulic fracturing units 12. In someexamples, the power harness 138 may be mounted on a trailer or a truckbody for portability (e.g., on a high-pressure iron manifold trailer) orsupported by the ground. In some examples, the power harness 138 mayinclude a plurality of power receptacles located along its length andconfigured to facilitate connection with a power plug of a respectivepower cable 112 from each of the respective hydraulic fracturing units12 to provide a power link between each of the hydraulic fracturingunits 12. In some examples, any excess electric power generated by oneor more of the hydraulic fracturing units 12 may be electricallysupplied to the power harness 138 via the respective power cableassembly 110. Such excess power may be electrically communicated to anyof the hydraulic fracturing units 12 lacking sufficient electric powervia the respective power cable assembly 110.

In the example shown in FIG. 15, the power harness 138 includes a firstpower harness line 140 a and a second power harness line 140 bconfigured to supply electric power to the first bank 46 and the secondbank 48 of the hydraulic fracturing units 12, respectively. In someexamples, an intermediate power cable 142 may be provided toelectrically connect the first power harness line 140 a and the secondpower harness line 140 b to one another, for example, so that electricpower may be shared between the first power harness line 140 a and thesecond power harness line 140 b.

FIG. 16 is a schematic diagram showing another example system 100 forsupplying fuel, enabling communications, and conveying electric powerassociated with operation of a plurality of hydraulic fracturing units12 according to embodiments of the disclosure. The example system 100 issimilar to the example system 100 shown in FIG. 15, except that that theexample 100 shown in FIG. 16 includes an electrical power source 116located remote from the hydraulic fracturing units 12 (e.g., notmechanically connected to any of the chassis 30 of the hydraulicfracturing units 12). The electrical power source 116 may beelectrically connected to the first and second power harness lines 140 aand 140 b via first and second additional lengths of power cable 114 aand 114 b, respectively. The first and second power harness lines 140 aand 140 b may be electrically connected to each of hydraulic fracturingunits 12 via their respective power cable assemblies 110, for example,as shown in FIG. 16.

FIG. 17A is a perspective view of an example quick connect coupling 144for coupling two fuel lines 146 to one another shown in an uncoupledcondition according to embodiments of the disclosure. FIG. 17B is aperspective view of the example quick connect coupling 144 shown in FIG.17A shown in a coupled condition according to embodiments of thedisclosure. The quick connect coupling 144 may be used with the manifoldlines 32 disclosed herein, for example, to couple an inlet end 34 of afirst manifold line 32 to an outlet end 36 of a fuel line in flowcommunication with a fuel source and/or to an outlet end 36 of anothermanifold line 32 of another hydraulic fracturing unit 12 upstreamrelative to the first manifold line 32. In addition, the outlet end 36of the first manifold line 32 may be coupled to an inlet end 34 of yetanother manifold line 32 of yet another hydraulic fracturing unit 12downstream relative to the first manifold line 32 or to a blockingdevice configured to prevent flow communication from the outlet end ofthe first manifold line 32. This example configuration may facilitateuse of the manifold line 32 to connect manifold lines 32 of multiplehydraulic fracturing units 12 in series or individually to a fuel linefrom a fuel source.

As shown in FIG. 17A, an outlet end 36 of a first manifold line 32 mayinclude an outlet coupling 44 of the quick connect coupling 144, and theinlet end 34 of a second manifold line 32 may include an inlet coupling40 of the quick connect coupling 144. In some examples, this may bereversed. As shown in FIG. 17A, the example outlet coupling 44 mayinclude an annular recess 146 configured to receive an annularprojection 148 of the inlet coupling 40. In some examples, the outletcoupling 44 may also include a handle 150 (e.g., an annular handle)configured to facilitate rotation of the outlet coupling 44 relative tothe inlet coupling 40, once the annular projection 148 is received inthe annular recess 146 of the outlet coupling 44. The annular projection148 may define a groove or slot 152 configured to receive a pin 154associated with the annular recess 146. When coupling the outletcoupling 44 to the inlet coupling 40, the annular projection 148 isinserted into the annular recess 146, such that the pin 154 is alignedwith a leading edge of the groove or slot 152, so that the annularprojection 148 can be inserted into the annular recess 146, whiletwisting the outlet coupling 44 relative to the inlet coupling 40, sothat the pin 154 travels in the groove or slot 152 until the pin 154 isable to engage a notch 156 in the groove or slot 152, thereby lockingthe rotational relationship between the outlet coupling 44 and the inletcoupling 40, for example, as shown in FIG. 17B, which shows the examplecouplings 40 and 44 engaged with one another. In some examples, thegroove or slot 152 may be configured such that the outlet coupling 44engages with the inlet coupling 40 upon twisting the outlet coupling 44about one-quarter turn relative to the inlet coupling 40. Other amountsof relative twist for coupling are contemplated. In some examples, thequick connect coupling 144 may include one or more fluid sealsconfigured to prevent fuel from leaking from the quick connect coupling144. In some examples, the quick connect coupling shown in FIGS. 17A and17B may include a pressure safety lock.

FIG. 17C is a perspective view of one-half of another example quickconnect coupling 144 for coupling two fuel lines to one another shown inan uncoupled condition according to embodiments of the disclosure. Theexample one-half quick connect coupling 144 shown in FIG. 17C may beconfigured to threadedly engage another half of the quick connectcoupling 144 (e.g., via complimentary male and female threads). In someexamples, the quick connect coupling 144 shown in FIG. 17C may include atransfer-loading safety quick coupler.

In some examples, the quick connect coupling 144 may facilitate quicklycoupling two or more manifold lines 32 to one another, and/or quicklycoupling a manifold line 32 to a fuel line from a fuel source, to a fuelhub, and/or to a blocking device configured to prevent the flow of fuelfrom the outlet end of the manifold line 32. This may facilitateconnection and/or disconnection of manifold lines 32 during set-up orbreak-down of the hydraulic fracturing system 16. In some examples, thequick connect coupling 144 may facilitate such set-up and assemblywithout the use of tools. In some examples, the quick connect couplings144 may help prevent improperly coupling two inlets to one another ortwo outlets to one another, which may prevent unintended problems withthe fuel delivery system.

FIG. 18 is a perspective view of an example communications coupling 158for coupling a communications cable from one device to another deviceaccording to embodiments of the disclosure. In some examples, thecommunications coupling 158 may be configured to couple an end of alength of communications cable 104 of a communications assembly 102associated with a hydraulic fracturing unit 12 to a communicationsinterface of, for example, another hydraulic fracturing unit 12, acommunications interface at a data center 106, and/or a communicationsinterface at a communications hub 120, for example, such as thosedescribed herein. The communications coupling 158 may, in some examples,be configured to provide a weather-tight quick connection, for example,such as a mil-spec connector. The communications coupling 158 mayinclude a mating pair (e.g., a plug and a receptacle), including a male(e.g., pin) or female (e.g., socket) contact. In some examples, one ormore of the coupling halves (e.g., the male or female halves) and/or therespective contacts may be floating, for example, to minimize mechanicalstress at the coupling 158. In some examples, the communication cables104 may have a capacity ranging from 12 volts to 24 volts and may beshielded to prevent communication from high power energy sources fromdistorting signals communicated via the communications cables 104.

In some examples, the communications coupling 158 may facilitate quicklycommunicatively coupling two or more devices or machines to one another.This may facilitate connection and/or disconnection of communicationscables 104 during set-up or break-down of the hydraulic fracturingsystem 16. In some examples, the communications coupling 158 mayfacilitate such set-up and assembly without the use of tools. In someexamples, the communications couplings 158 may be configured to haveunique communication coupling pairs to prevent coupling thecommunications cable 104 into an incorrect receptacle, thereby reducingthe likelihood of an incorrect rigging and incorrect transfer of data.Other types of communications couplings are contemplated.

FIG. 19 is a perspective view of an example power coupling 160configured to couple a power cable 112 to a device according toembodiments of the disclosure. As shown in FIG. 19, the power coupling160 may include a power plug 162 connected to an end of a power cable112, and a power receptacle 164. For example, the power cable 112 may beconnected to a first hydraulic fracturing unit 12, and the powerreceptacle 164 may be connected to another hydraulic fracturing unit 12,a power hub 122, and/or an electrical power source 116. The power plug162 may be configured to be inserted into a power receptacle 164 toprovide electric power transfer between a device or machine coupled tothe power cable 112 and power plug 162, and the device or machinecoupled to the power receptacle 164. In some examples, the powercoupling 160 include a shore power connector-type that may be configuredto be water-proof, locking, and/or capable of handling three-phase, 480volts, and/or 400 amps, although power couplings of other types and/orhaving different capabilities are contemplated.

In some examples, the power coupling 160 may facilitate quicklyelectrically coupling two or more devices or machines to one another.This may facilitate connection and/or disconnection of power cables 112during set-up or break-down of the hydraulic fracturing system 16. Insome examples, the power coupling 160 may facilitate such set-up andassembly without the use of tools.

Having now described some illustrative embodiments of the invention, itshould be apparent to those skilled in the art that the foregoing ismerely illustrative and not limiting, having been presented by way ofexample only. Numerous modifications and other embodiments are withinthe scope of one of ordinary skill in the art and are contemplated asfalling within the scope of the invention. In particular, although manyof the examples presented herein involve specific combinations of methodacts or system elements, it should be understood that those acts andthose elements may be combined in other ways to accomplish the sameobjectives. Those skilled in the art should appreciate that theparameters and configurations described herein are exemplary and thatactual parameters and/or configurations will depend on the specificapplication in which the systems and techniques of the invention areused. Those skilled in the art should also recognize or be able toascertain, using no more than routine experimentation, equivalents tothe specific embodiments of the invention. It is, therefore, to beunderstood that the embodiments described herein are presented by way ofexample only and that, within the scope of any appended claims andequivalents thereto, the invention may be practiced other than asspecifically described.

This is a continuation of U.S. Non-Provisional application Ser. No.15/929,708, filed May 18, 2020, titled “FUEL, COMMUNICATIONS, AND POWERCONNECTION SYSTEMS AND RELATED METHODS,” which claims priority to andthe benefit of U.S. Provisional Application No. 62/900,100, filed Sep.13, 2019, titled “ON BOARDING HOSES AND ELECTRICAL CONNECTIONS”, U.S.Provisional Application No. 62/900,112, filed Sep. 13, 2019, titled“FUEL LINE CONNECTION SYSTEM AND METHODS FOR SAME”, and U.S. ProvisionalApplication No. 62/704,401, filed May 8, 2020, titled “FUEL,COMMUNICATIONS, AND POWER CONNECTION SYSTEMS AND RELATED METHODS”, theentire disclosures of all of which are incorporated herein by reference.

Furthermore, the scope of the present disclosure shall be construed tocover various modifications, combinations, additions, alterations, etc.,above and to the above-described embodiments, which shall be consideredto be within the scope of this disclosure. Accordingly, various featuresand characteristics as discussed herein may be selectively interchangedand applied to other illustrated and non-illustrated embodiment, andnumerous variations, modifications, and additions further can be madethereto without departing from the spirit and scope of the presentinvention as set forth in the appended claims.

What is claimed is:
 1. A fuel line connection assembly for providingflow communication between a fuel source and a first gas turbine engineof a plurality of gas turbine engines, the fuel line connection assemblycomprising: a manifold line defining an inlet end, an outlet end, and aflow path for fuel extending between the inlet end and the outlet end;an inlet coupling positioned proximate the inlet end and configured tobe connected to a fuel line providing flow communication with the fuelsource; an outlet coupling positioned proximate the outlet end andconfigured to be connected to one of an inlet end of one or more of: (a)another manifold line or (b) a blocking device configured to preventflow from the outlet end of the manifold line; a distribution lineconnected to the manifold line and configured to provide flowcommunication between the manifold line and the first gas turbineengine; and a valve connected to one or more of: (a) the manifold lineor (b) the distribution line, the valve being configured to changebetween an open condition through which fluid flows and a closedcondition preventing fluid flow, the valve further configured to one offacilitate flow communication or prevent flow communication between thefuel source and the first gas turbine engine, wherein the fuel lineconnection assembly is configured to one of: provide flow communicationbetween a second gas turbine engine of the plurality of gas turbineengines upstream of the first gas turbine engine and a third gas turbineengine of the plurality of gas turbine engines downstream of the firstgas turbine engine; or provide flow communication solely between thefuel source and the first gas turbine engine.
 2. The fuel lineconnection assembly of claim 1, further comprising a sensor disposed inone or more of: (a) the manifold line or (b) the distribution line, thesensor being configured to generate a signal indicative of pressureassociated with flow of fuel to the first gas turbine engine.
 3. Thefuel line connection assembly of claim 1, further comprising a filterdisposed in the distribution line between the manifold line and thefirst gas turbine engine and configured to filter one or more ofparticulates or liquids from fuel in flow communication with the firstgas turbine engine.
 4. The fuel line connection assembly of claim 3,further comprising a sensor disposed in the distribution line betweenthe filter and the first gas turbine engine and configured to generate asignal indicative of pressure associated with flow of fuel between thefilter and the first gas turbine engine.
 5. The fuel line connectionassembly of claim 1, wherein the valve comprises a first valve and thefuel line connection assembly further comprises: a second valve disposedin the distribution line and configured to change between an opencondition through which fluid flows and a closed condition preventingfluid flow, the second valve further configured to one of facilitateflow communication or prevent flow communication between a filterconfigured to filter one or more of particulates or liquids from fueland the first gas turbine engine; a test line in flow communication withthe distribution line between the filter and the first gas turbineengine and configured to provide flow communication between a pressuresource and the filter; and a third valve disposed in the test line andconfigured to change between an open condition through which fluid flowsand a closed condition preventing fluid flow, the third valve furtherconfigured to one of facilitate flow communication or prevent flowcommunication between the pressure source and the filter.
 6. The fuelline connection assembly of claim 5, further comprising a fourth valvedisposed between the pressure source and the filter and configured tochange between an open condition through which fluid flows and a closedcondition preventing fluid flow, the fourth valve further configured toone of facilitate flow communication or prevent flow communicationbetween the pressure source and the filter, and to release pressure inthe test line between the pressure source and the third valve.
 7. Thefuel line connection assembly of claim 6, further comprising one or moreactuators connected to one or more of the first valve, the second valve,the third valve, or the fourth valve and configured cause one or more ofthe first valve, the second valve, the third valve, or the fourth valveto change conditions.
 8. The fuel line connection assembly of claim 5,further comprising a sensor disposed between the second valve and thethird valve and configured to generate a signal indicative of pressurein one or more of the distribution line or the manifold line.
 9. Thefuel line connection assembly of claim 5, further comprising: a sensordisposed in one of the manifold line or the distribution line andconfigured to generate a signal indicative of pressure in one or more ofthe manifold line or the distribution line; and a controller incommunication with the sensor, the first valve, the second valve, thethird valve, and the pressure source, the controller configured to:cause operation of one or more of the first valve, the second valve, orthe third valve, and receive the signal indicative of pressure.
 10. Thefuel line connection assembly of claim 9, wherein the controller isfurther configured to determine presence of a leak in the fuel lineconnection assembly based at least in part on the signal indicative ofpressure.
 11. The fuel line connection assembly of claim 9, wherein thecontroller is configured to: cause the first valve to be in the opencondition; cause the second valve to be in the closed condition; causethe third valve to be in the open condition; cause the pressure sourceto increase pressure in one or more of the distribution line or themanifold line; and determine the presence of a leak in the fuel lineconnection assembly based at least in part on the signal indicative ofpressure.
 12. The fuel line connection assembly of claim 11, furthercomprising a fourth valve disposed between the pressure source and thethird valve and configured to change between an open condition throughwhich fluid flows and a closed condition preventing fluid flow, whereinthe controller is configured to cause: the pressure source to ceaseincreasing pressure in the one or more of the distribution line or themanifold line, and the fourth valve to be in the open condition torelease pressure from one or more of the distribution line or themanifold line.
 13. The fuel line connection assembly of claim 1,wherein: the manifold line is a first manifold line; the inlet couplingof the first manifold line is configured to connect with an outletcoupling of a second manifold line upstream relative to the firstmanifold line; the outlet coupling of the first manifold line isconfigured to connect with one of an inlet coupling of a third manifoldline or a blocking device configured to prevent flow from the outlet endof the first manifold line.
 14. The fuel system of claim 13, wherein:the inlet coupling of the first manifold line comprises a first quickconnect coupling configured to connect the inlet end of the firstmanifold line in a fluid-tight manner with a second quick connectcoupling of an outlet end of the second manifold line; and the outletcoupling of the first manifold line comprises a second quick connectcoupling configured to connect the outlet end of the first manifold linein a fluid-tight manner with one of a first quick connect coupling of aninlet end of the third manifold line or a first quick connect couplingof the blocking device.
 15. A fuel delivery system configured to supplyfuel to a plurality of gas turbine engines connected to a plurality ofpumps of a hydraulic fracturing system, the fuel delivery systemcomprising: a plurality of fuel line connection assemblies comprising: amanifold line defining an inlet end, an outlet end, and a flow path forfuel extending between the inlet end and the outlet end; an inletcoupling proximate the inlet end and configured to be connected to afuel line providing flow communication with the fuel source; an outletcoupling proximate the outlet end and configured to be connected to oneof an inlet end of another manifold line or a blocking device configuredto prevent flow from the outlet end of the manifold line; a distributionline connected to the manifold line and configured to provide flowcommunication between the manifold line and the first gas turbineengine; and a valve in one of the manifold line or the distribution lineand configured to change between an open condition through which fluidflows and a closed condition preventing fluid flow, the valve furtherconfigured to one of facilitate flow communication or prevent flowcommunication between the fuel source and the first gas turbine engine,wherein: a first fuel line connection assembly of the plurality of fuelline connection assemblies is in flow communication with a first outletcoupling of the fuel source via an inlet coupling of the first fuel lineconnection assembly; and a second fuel line connection assembly of theplurality of fuel line connection assemblies is in flow communicationwith one of an outlet coupling of the first fuel line connectionassembly or a second outlet coupling of the fuel source via an inletcoupling of the second fuel line connection assembly.
 16. The fueldelivery system of claim 15, wherein: the second fuel line connectionassembly of the plurality of fuel line connection assemblies is in flowcommunication with the outlet coupling of the first fuel line connectionassembly; and a third fuel line connection assembly of the plurality offuel line connection assemblies is in flow communication with an outletcoupling of the second fuel line connection assembly via an inletcoupling of the third fuel line connection assembly.
 17. The fueldelivery system of claim 15, wherein: the second fuel line connectionassembly of the plurality of fuel line connection assemblies is in flowcommunication with the second outlet coupling of the fuel source via theinlet coupling of the second fuel line connection assembly; and a thirdfuel line connection assembly of the plurality of fuel line connectionassemblies is in flow communication with a third outlet coupling of thefuel source via an inlet coupling of the third fuel line connectionassembly.
 18. The fuel delivery system of claim 17, wherein the fuelsource is in flow communication with a hub comprising the first outletcoupling of the fuel source, the second outlet coupling of the fuelsource, and the third outlet coupling of the fuel source.
 19. The fueldelivery system of claim 17, wherein: the fuel source is in flowcommunication with a first hub and a second hub; the first hub comprisesthe first outlet coupling of the fuel source and the second outletcoupling of the fuel source; and the second hub comprises the thirdoutlet coupling of the fuel source.